The invention relates to a method of manufacturing an optoelectronic semiconductor device with a semiconductor body, whereby a semiconductor layer structure is provided on a semiconductor substrate by means of a non-selective growing process, an etching process and a selective growing process, a first portion of this structure comprising a comparatively thin active layer and a second portion situated adjacent and against the first portion comprising a comparatively thin radiation-guiding layer, while said semiconductor layer structure further comprises a cladding layer situated over the thin layers.
Such a method is highly suitable inter alia for manufacturing diode lasers comprising a waveguide. The waveguide then comprises, for example, a non-absorbing minor region or an extension of the resonance cavity which is provided, for example, with a grating. Other devices having an active element such as a diode laser, a laser amplifier, or a photodiode integrated with a waveguide may also be advantageously manufactured by such a method. In that case, components such as lasers, amplifiers, detectors, waveguides, modulators, switches, etc, may be integrated.
Such a method is known from European Patent Application 90902703.9 published under no. 0 411 145 on Jun. 6, 1991. It is described therein how in this manner a DFB (=Distributed Feed Back) diode laser with an active layer and an optical modulator with a radiation-guiding layer are integrated on a substrate. A 0.15 .mu.m thick InGaAsP (.lambda.=1.55 .mu.m) active layer 4 and a 0.5 .mu.m thick InP cladding layer 5 are provided on an InP substrate 1 (see column 6 and FIGS. 9 to 13 of EP 0 411 145) by means of a non-selective growing process. These layers are locally removed by etching outside a first portion of the layer structure. After this, a second portion of the layer structure situated adjacent and against the first portion is provided here by a selective growing process. The second portion comprises an InGaAsP (.lambda.=1.4 .mu.m) radiation-guiding, --and here also radiation-absorbing--layer 6 and an InP cladding layer 7, which adjoin to the active layer 4 and the cladding layer 5, respectively, in the first portion substantially contiguously.
A disadvantage of the known method is that in this method unevennesses and/or openings can arise in the cladding layer near the surface of and at the area of the transition between the two portions of the layer structure. Such defects cause problems in the implementation of various processes usual in manufacture, such as photolithographic, metallization, deposition or etching processes.